The invention relates to a program carrier for switching chronometer systems having a motor driven drum which comprises a plurality of switch elements at its circumference which can be displaced between an active and an inactive position, and which interact with a sampler in their active position for the control of a switch.
Given a known switching chronometer system, an electrical switch clock of the type initially described (see German Letters Pat. No. 28 13 069, incorporated herein by reference), the program carrier comprises at least two parts seated and fixed relative to one another, a motor driven drum, and an index plate plugged onto the drum and in engagement therewith. For this purpose, the generated surface of the drum is provided with guide slots that are open at one end and extend in the direction of the drum axis in radially proceeding manner, and with movable arms of switch elements interengaging into said guide slots. Here, the switch elements are united via the movable arms to form a one-piece index plate.
This mechanism has associated with it the considerable disadvantage that the manufacturing tolerances of the individual, movable arms and of the switch elements in engagement with the generated surface of the drum which are disposed there must be extremely precise with respect to the outside diameter of the generated surface of the drum. This is true in order to assure the desired effect of having two secured switch positions of the individual switch elements on the generated surface of the drum.